What is a CDN?

What is a CDN?

Very simply put, a Content Delivery Network (CDN) is a group of servers that are distributed all over the world; these servers work together to deliver content quickly to users on the Internet. A CDN helps to allow the quick transfer of assets needed for loading content. Content, in this case, includes HTML, JavaScript, stylesheets, images, videos, and more. The majority of all websites on the internet are run through some sort of CDN.

How can a CDN help?

A CDN that is configured and optimized properly can protect a website against malicious attacks, such as Distributed Denial of Service (DDoS) attacks. This is because CDN services use what is called a proxy; this is a server that acts as a wall in front of multiple web servers and will forward requests to those servers.

There are quite a few reasons that one might want any kind of proxy service used on their website. One reason is to avoid browsing restrictions, such as country- or state-wide and school/institution restrictions. Another reason is to do the opposite of that, which is blocking access to certain content. We feel that one of the best reasons to make sure you’re using a proxy is for privacy reasons (adding to the security). This happens because the actual IP address of the website is hidden, and instead only the IP address of the proxy server is visible.

Why a REVERSE proxy, specifically?

A general, forward proxy sits in front of client machines; this is to ensure that no origin server communicates directly with the client, like a middleman. A reverse proxy is the opposite; it sits in front of the origin server, and ensures that no client (e.g. web browser) communicates directly with that origin server. Just below, we’ll get into some benefits of using a reverse proxy specifically.

  • Caching – A reverse proxy is able to cache content on the website (unlike a forward proxy), which results in faster load times.

“For example, if a user in Paris visits a reverse-proxied website with web servers in Los Angeles, the user might actually connect to a local reverse proxy server in Paris, which will then have to communicate with an origin server in L.A. The proxy server can then cache (or temporarily save) the response data. Subsequent Parisian users who browse the site will then get the locally cached version from the Parisian reverse proxy server, resulting in much faster performance.” ~ Cloudflare

  • SSL Encryption – Encrypting and decrypting SSL requests can be computationally expensive (using a lot of resources); a reverse proxy can be configured to decrypt all incoming requests and encrypt all outgoing responses, freeing up resources on the origin server.
  • Protection from attacks – With a reverse proxy in place, a website will not need to reveal the origin’s server IP address. This makes it much harder for attackers to leverage a targeted attack against the website (DDoS, for example). Instead, the attackers will only be able to target the reverse proxy, which will have higher security levels and more resources to protect the website.
  • Load balancing – A popular website that gets a lot of visitors regularly may not be able to handle all the traffic utilizing only one origin server. Using a reverse proxy, the website can be distributed among a group of different servers, all handling various requests for that site. The load balancing solution distributes incoming traffic evenly among the group of servers to prevent any one server from being overloaded. If a server does happen to fail, the other remaining servers can jump in together to handle the traffic.

Okay. So… how does a CDN work?

In a nutshell, a CDN is a network of servers that work together with the goal of delivering content as quickly, reliably, and securely as possible. A CDN puts exchange servers at exchange points between networks; this is the main way they improve speed and connectivity. The Internet exchange points (IXPs) are the main locations where different Internet providers connect to provide each other access to traffic from their own servers. By connecting to these high-speed and interconnected locations, CDNs can reduce costs and transit times in high speed data delivery.

How does a CDN work, map of servers in relation to user

Image from Cloudflare.


CDNs also make a number of optimizations to standard data transfers. Data centers are placed at various strategic locations around the globe, and are designed to ensure survival in the events of failure or Internet congestion.

But how does the CDN improve load times?

As many know, the amount of users will drastically drop off as the website takes longer and longer to fully load. CDNs can improve on that in a few ways:

  • CDNs essentially reduce the distance between users and website resources. Instead of the user always having to connect to the website’s origin server (the geographical location the server is physically located), the CDN lets the user connect to a geographically closer data center. Less travel time = faster load time.
  • CDNs can efficiently reduce the amount of data that is being transferred using methods such as file compression and minification. Smaller file size = quicker to load.
  • CDNs also optimize connection reuse and can enable TLS false start for websites that use TLS/SSL certificates.

Why should I think about using a CDN on my website?

Besides what is mentioned above, there are a few other excellent benefits to using a CDN that many people may not be aware of. By using certain CDNs, you can ensure your website is always online. Uptime is extremely important in today’s digital world, so in case of any hardware failures, spikes in traffic, malicious attacks, or otherwise, a well-rounded CDN has certain features that minimize downtime. These include load balancing (as mentioned above) and intelligent failover (if one or more of the CDN servers go offline, traffic can be redistributed to other operational servers), among other features.

CDNs can also protect your data, who knew?! Optimization of the TLS/SSL certificates can help ensure proper and strong security levels at all times.

Last, depending on your hosting provider, chances are you have a bandwidth limit on your website(s). Every time an origin server responds to a client request, hosting bandwidth is consumed; this is usually a fairly small amount of bandwidth each time, but depending on the number of visitors your website experiences, this number can rise quickly. Because CDN servers are spread out, by using a CDN your bandwidth requests may come from the CDN servers instead of your origin server depending on where the client is located. Simply put, less work your origin server has to do so it can focus on why it’s there – to give your clients or customers a great experience.

When you work with IntoClicks, we’d always love to have you set up with our Managed Domain services though some may prefer to handle these things themselves. By signing up for our Managed Domain services, however, you can feel comforted and safe in the fact that your domain and anything associated with it are in good hands. We’ll handle registration and renewal, DNS management, additional security, and we’ll set up your website on CDN servers so you can receive all the benefits mentioned in this article – all at a low monthly subscription cost. If you’re interested in setting up a CDN for your website(s), contact us for more information.

We can help – we’re IntoClicks.

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